Variations of Earthquake Properties Before, During, and After the 2019 M7.1 Ridgecrest, CA, Earthquake
Variations of Earthquake Properties Before, During, and After the 2019 M7.1 Ridgecrest, CA, Earthquake
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DOI：
10.1029/2020gl089650
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发表时间：
2020-09-28
影响因子：
5.2
通讯作者：
Ben-Zion, Yehuda
中科院分区：
文献类型：
--
作者：
Cheng, Yifang;Ben-Zion, Yehuda
我们试图通过分析2019年山脊地震序列的地震活动性、效力值和导致序列和序列期间地震的震源机制的时空变化来阐明与序列相关的过程。在他们(w)7.1主震前的20年间，正常断裂事件的比例从25%逐渐下降到10%以下，表明剪切应力长期增加。他们(w)6.4和m (w)7.1破裂终止于地震速度变化强烈的区域或与其他断层产生拦阻屏障的交叉处。余震具有震源机制高度多样化的特点，并在主要断裂周围5-10公里宽的区域内产生体积脆性变形。他们(w)7.1事件的早期余震延伸到典型发震深度以下的广泛区域，与脆性-韧性过渡的短暂加深相一致。脊峰地震序列在包括名义发震区以下的周围地壳中造成了相当大的岩石破坏。
We attempt to clarify processes associated with the 2019 Ridgecrest earthquake sequence by analyzing space-time variations of seismicity, potency values, and focal mechanisms of earthquakes leading to and during the sequence. Over the 20 years before theM(w)7.1 mainshock, the percentage of normal faulting events decreased gradually from 25% to below 10%, indicating a long-term increase of shear stress. TheM(w)6.4 andM(w)7.1 ruptures terminated at areas with strong changes of seismic velocity or intersections with other faults producing arresting barriers. The aftershocks are characterized by highly diverse focal mechanisms and produced volumetric brittle deformation concentrated in a 5-10 km wide zone around the main ruptures. Early aftershocks of theM(w)7.1 event extended over a wide area below typical seismogenic depth, consistent with a transient deepening of the brittle-ductile transition. The Ridgecrest earthquake sequence produced considerable rock damage in the surrounding crust including below the nominal seismogenic zone.